This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. The overall goal of the project is to examine if the migration of trunk neural crest cells (NCCs) to the Dorsal Root Ganglion (DRG) involves SDF1/CXCR4 signaling and to identify regulatory factors that mediate this process. Defective migration of trunk NCCs can cause perinatal lethality and affect the development and formation of the peripheral nervous system. Towards this end, we generated chicken SDF1 and CXCR4 riboprobes, and utilized them in in situ hybridization (ISH) analyses to determine the spatiotemporal expression of the two genes during embryonic development. The hypothesis being addressed is that trunk NCCs express CXCR4 and migrate towards mesodermal regions of high SDF-1 concentration where they differentiate into the DRG. Chicken embryos (Hamilton-Hamburger (HH) stages ~7 to 22) were used for the study as their developmental stages are well defined and are more amenable to analysis and manipulation. Gene expression profiling of SDF1 and CXCR4 spanning these developmental stages in the chick embryo has largely been accomplished. Using specific antibodies (anti-HNK-1 for NCCs and anti-Islet-1 for the DRG), we are now determining if the expression patterns of CXCR4 and SDF-1 correspond to the developmental paths undertaken by migrating NCCs to become DRG. To identify factors regulating NCC migration via SDF1/ CXCR4 signaling (e.g., TGF[unreadable]1 and BMP4) and the effect of this signaling on putative downstream targets, such as IP3 kinase, PC12 cells (derived from the adrenal gland and of neural crest origin) are being used as a model system in experiments employing transwells.